Colorants or coloring agents are mainly used to impart a distinctive appearance to the pharmaceutical dosage forms.
We can also say that the colorants are the cosmetics for the pharmaceutical preparations, because the aesthetic appearance of dosage forms can be enhanced by using suitable colorants.
2. INTRODUCTION
Colorants or coloring agents are mainly used to
impart a distinctive appearance to the
pharmaceutical dosage forms.
We can also say that the colorants are the
cosmetics for the pharmaceutical preparations,
because the aesthetic appearance of dosage
forms can be enhanced by using suitable
colorants.
3. Pharmaceutical preparations are
colored for following reasons:
1) Increases acceptability
• Unattractive medication can be made more
acceptable to the patient by the use of color,
• Color can also be used to make a preparation
more uniform when an ingredient in the
formulation has itself a variable appearance
from batch to batch.
4. 2) For identification
• It helps to identify a product in it manufacturing
and distribution stages.
• The use of different colors for different
strengths of the same drug can also help
eliminate errors.
• A specific example is the anesthetic Trichloro
ethylene, which may be colored blue to
distinguish it from chloroform which it
resembles in physical characteristics.
5. 3) Stability purpose
• Some of the insoluble colors or pigments have
the additional benefit when used in tablet
coatings or gelatin shells of providing useful
opacity, which can contribute to the stability of
light‐sensitive active materials in the tablet or
capsule formulation.
6. Ideal properties of a colorant
• Non-toxic and have no physiological activity.
• Free from harmful impurities
• Is a definite chemical compound because then
only its coloring power will be reliable
• Its Tinctorial (coloring) power should be high so
that only small quantities are required.
7. Unaffected by light, tropical temperatures, hydrolysis
and micro‐organisms and, therefore, be stable on
storage.
Unaffected by oxidizing or reducing agents and pH
changes.
Compatible with medicaments and not interfere with
them.
Ready solubility in water is desirable in most cases
but some oil‐soluble and spirit‐soluble colors are
necessary.
8. Does not interferes with the tests and assays
to which the preparations containing it are
subject.
Should not be appreciably adsorbed on to
suspended matter.
Free from objectionable taste and odour.
9. The food, drug, and cosmetic act
The Food Drug and Cosmetic Act of 1938 created three categories of
Dyes
FD&C colors: These are colorants that are certifiable for use in foods,
drugs, and cosmetics.
D&C colors: These are dyes and pigments considered safe for use in
drugs and cosmetics when in contact with mucous membranes or
when ingested.
External D&C colors: These colorants, due to their oral toxicity, are not
certifiable for use in products intended for ingestion but are
considered safe for use in products applied externally
10. Classification
A. Organic dyes and their lakes
B. Inorganic or mineral colors
C. Natural colors or vegetable and animal colors
11. Organic dyes and their lakes
• Dyes are synthetic, chemical compounds that
exhibit their coloring power or tinctorial
strength when dissolved in a solvent
Examples include:
Erythrosine
Patent Blue V
12. Lakes
• Lakes have been defined by the FDA as the
"Aluminum salts of FD&C water soluble dyes
extended on a substratum of alumina".
• Lakes prepared by extending the calcium salts
of the FD&C dyes.
13. Inorganic or mineral colors
• Stability towards light is an important
characteristic displayed by this materials, some
of which have a useful opacifying capacity, e,g.
Titanium dioxide.
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14. • The most important application of, mineral
coloring in a present‐day medicament is the
use of a mixture of red and yellow ferric oxides
to give calamine a flesh color.
Titanium dioxide is used to color and opacify
hard gelatin capsules.
15. Natural colors or vegetable and animal
colors
• This is a chemically and physically diverse
group of materials.
• Some of this colors are the products of
chemical synthesis rather than extraction from
a natural source
For example, β‐carotene is synthetic in origin.
The term frequently applies to such materials is
‘nature identical’, which in many ways is more
descriptive.
16. • natural colors are not as stable to light as the
other group of colors.
• They do, however, advantage in that they have
a wide acceptability.
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17. Widely used colorants in
pharmaceuticals
• FD&C Blue No. 1 – Brilliant Blue, (blue shade)
• FD&C Blue No. 2 – Indigotine, (indigo shade)
• FD&C Red No. 3 – Erythrosine, (pink shade)
• FD&C Red No. 40 – Allura Red, (red shade)
• FD&C Yellow No. 5 – Tartrazine, (yellow
shade)
• FD&C Yellow No. 6 – Sunset Yellow, (orange
shade)
18. Conclusion
The colorants works as the cosmetics for the
pharmaceutical formulations, thus, selection
of appropriate colorant for a specific
pharmaceutical dosage form plays an
important role in manufacturing of the
pharmaceutical dosage forms.